APPLICANT'S ABSTRACT: Drinking related problems are highly prevalent among patients using primary health care. Although many proven techniques and instruments exists, research evidence indicates that little identification and intervention is provided for these populations, and important opportunities to intervene are lost. The primary aim of this study is to examine factors that may predict practice of screening and brief intervention in 1) a random sample of physicians and nurses in Contra Costa County, California, collected as part of this application; and 2) practitioners and support staff from eight managed care organizations, involving secondary analysis of data collected as part of an ongoing study of screening and brief intervention at the University of Connecticut. Both data sets address each of the research questions in this application. Several explanations of why health professionals do not often screen for alcohol problems exist; many of these reflect their beliefs about alcohol problems, screening and brief intervention. Hypotheses examine beliefs about the effectiveness of intervention; time involved, resources available, self-efficacy and organizational constraints; normative beliefs regarding support from reference groups; and individual knowledge about substance abuse as they relate to the actual practice of screening and brief intervention. Data collection involves self-administered questionnaires. Analysis includes a path model taking into account behavioral, control and normative beliefs; intention; and the role of objective knowledge as it relates to screening and brief intervention. This research has important implications for improving the application of screening and brief intervention strategies in health care organizations.